DESCRIPTION (Applicant?s abstract) This proposal seeks to provide an opportunity for the Principal Investigator (PI) to gain knowledge and skills in genetic epidemiology, under the direct supervision of a highly qualified sponsor, to further enhance his potential to develop into an independent investigator. The PI, who is trained in clinical Pulmonary and Critical Care Medicine, has recently obtained a M.P.H. degree, in addition to completing a respiratory epidemiology fellowship and the initial requirements for a Dr. P.H. degree in Genetic Epidemiology. The first two years of this proposal will incorporate needed course work, seminars, and hands-on experience in genetic analysis and molecular biology techniques to enable the PI to undertake an intensive research experience in the latter three years of the proposal. The overall scientific goal of this proposal is to study the genetic influences on the development of asthma and asthma-related phenotypes in a large and homogeneous subset of Hispanic subjects. We hypothesize that a subset of chromosomal regions previously linked to asthma-related phenotypes will contribute to the expression of asthma in a genetically isolated Costa Rican population. To test this hypothesis, we will conduct a directed screen on two chromosomal regions (5q31 - q33 and 12q15- q24.1) By identifying genetic determinants of asthma among subjects of Latin American ancestry, this proposal could greatly contribute to our understanding of the pathogenesis of asthma, particularly among Hispanics. In addition, it will create a bank of phenotypic and genotypic information that will facilitate further hypothesis testing in a unique patient cohort.